Higher selenium status is associated with adverse blood lipid profile in British adults

Abstract

Recent findings have raised concern about possible associations of high selenium exposure with diabetes and hyperlipidemia in the US, a population with high selenium status. In the UK, a population with lower selenium status, there is little data on the association of selenium status with cardio-metabolic risk factors in the general population. We examined the association of plasma selenium concentration with blood lipids in a nationally representative sample of British adults. A cross-sectional study was conducted among 1042 white participants (aged 19-64 y) in the 2000-2001 UK National Diet and Nutrition Survey. Plasma selenium was measured by inductively coupled-plasma mass spectrometry. Total and HDL cholesterol were measured in nonfasting plasma samples. Mean plasma selenium concentration was 1.10 +/- 0.19 micromol/L. The multivariate adjusted differences between the highest (> or =1.20 micromol/L) and lowest (<0.98 micromol/L) quartiles of plasma selenium were 0.39 (95% CI 0.18, 0.60) mmol/L for total cholesterol, 0.38 (0.17, 0.59) for non-HDL cholesterol, and 0.01 (-0.05, 0.07) for HDL cholesterol. Higher plasma selenium (i.e., > or =1.20 micromol/L) was associated with increased total and non-HDL cholesterol levels but not with HDL in the UK adult population. These findings raise additional concern about potential adverse cardio-metabolic effects of high selenium status. Randomized and mechanistic evidence is necessary to assess causality and to evaluate the impact of this association on cardiovascular risk.

FIGURE 1

Adjusted differences (95% CI) in lipid fraction concentrations by plasma selenium, in the 2000–2001 UK NDNS. The curves (read in the scale to the left) represent the adjusted differences (and the gray shading, the 95% CI) in lipids of subjects with any given value of plasma selenium with respect to a subject with 0.95 μmol/L of plasma selenium (plasma selenium at the 20th percentile, which was used as reference). The differences are statistically significant for all the range where the gray shading does not include the dashed reference line that denotes a zero difference. Plasma selenium was modeled as restricted quadratic splines with nodes at the 5th, 50th, and 95th percentiles. Multivariable linear regression models were adjusted for age, sex, BMI, smoking status, daily cigarette consumption, daily alcoholic drinking units, daily physical activity score, household income group, educational level group, employment status, daily food energy, total fat intake, total cholesterol intake, polyunsaturated-to-saturated fatty acid ratio, vitamin/mineral supplement use, oral contraceptive use, and hormone replacement therapy. The histogram (read in the scale to the right) shows the distribution of plasma selenium in the study population.